Center link for rivetless chains



y 1951 A. w. LEMMON 2,552,897

CENTER LINK FOR RIVETLESS CHAINS Original Filed Jan. 19, 1945 2Sheets-Sheet 1 I I l l E 5 INVENTOR.

38 14:. EX/S M lawn mv y 1951 A. w. LEMMON 2,552,897

CENTER LINK FOR RIVETLESS CHAINS Original Filed Jan. 19, 1945Z-Sheets-Sheet 2 INVENTOR.

Patented May 15, 1951 CENTER LINK FOR RIVETLESS' CHAINS Alexis W.Lemmon, Upper Arlington, Ohio, as-

signor' to Jervis B. Webb Company, Detroit, Mich, a corporation ofMichigan Original application January 19, 1945, Serial No. 573,517, nowPatent No. 2,507,025, dated May 9, 1950. Divided and this applicationNovember 22, 1946, Serial No. 711,590

2 Claims. (Cl. 198-477 This invention relates to a particular type ofchain variously called Keystone, Rivetless or Weston chain which formany years has had wide application in conveyors, mining machinery andother industrial uses as well as a trolley conveyor bracket adapted tobe engaged by such chain as in moving a trolley along a conveyor track.

The original rivetless chain was the subject matter of Weston Patent No.870,704. In addition to its great strength, its principal features areits adaptability as a sprocket chain, the absence of rivets, and theease with which individual links may be removed from or added to thechain. The adaptation of this type of chain in providing a power drivefor a trolley conveyor line as disclosed in the patent to Jervis B;Webb, No. 1,729,759, has found wide application in the conveyorindustry. This invention is directed to certain improvements in theWeston chain and in the trolley conveyor bracket driven by such chainhaving for their object the strengthening of the chain to improve thefunctioning thereof in operation, the incorporation of a self-centeringfeature between the chain and trolley bracket and to effect certaineconomies in the cost of fabricating the same; this application being adivision of my prior application, Serial No. 573,517, filed January 19,1945, and now Patent No. 2,507,025, granted May 9, 1950.

The original rivetless chain to which the present. invention is directedand which formed the subject matter of the Weston Patent No. 870,704consists of a plurality of alternately arranged center links and sidebars as they are termed in the art. Each center link consists of anintegral piece of metal having a pair of laterally spaced side wallsjoined at their ends by curved end walls, said side and end wallsenclosing or surrounding an elongated slot. A pair of side bars eachhaving an elongated slot at each end is pivotally connected to each endof each center link by headed pins, each pin having a transverse head oneach end thereof similar to the headed end of a T-head machine bolt. Theside bars are formed at their ends with transversely extending recesseson their outer faces in which the heads of the pins are seated to lockthe pins in position after the center links and side bars have beencoupled together. Each of the center links has a narrowed centralportion which tapers outwardly adjacent to the ends of the link to formthickened portions at the link ends. The center links and side bars areassembled by holding the elongated slots in the ends of a pair of sidebars one on each side of the center link at the central portion of theelongated slot of the center link and in parallelism therewith, theninserting the headed end at one end of a headed pin through the threeslots, next turning the side bars at a right angle to the center linkand seating the heads of the pins in the transverse recesses formed inthe ends of the side bars, after which the pair of side bars and theheaded pin are slid toward the thickened end portion of the center linkwhereby said thickened portion holds the side bars spread apartsufficiently to maintain the transverse T-heads on each pin Within thetransverse recesses in the outer faces of the side bars, thus holdingthe side bars and center links pivotally secured together. When thecenter links and side bars are so assembled to form a length of chain,the side bars and center links are arranged in alternate relationshipalong said chain, each center link having connected to each end thereofa pair of spaced side bars and each such pair of side bars beingconnected at each end to an adjacent center link and so that pivotalmovement is permitted between the adjacent center links and sidebarsabout the center of said headed pins as an axis.

In the original Weston chain the center links thereof, although made asforgings, have the general form that would result if a fiat piece ofsteel approximately of an inch in thickness were bent to form anelongated link having the ends thereof curved and so that the inner faceof the bar at each end of the link forms a substantiallysemi-cylindrical bearing surface for the body portion of the connectingheaded pin.

In the original Weston chain the end portions of the center links, asshown in the Weston Patent No. 870,704 are approximately twice as wideas the central portion of the link and the barlike piece of metal whichforms the link is provided with a comparatively sharply inclined sectionor taper where the wider end portions connect with the thinner centralportion thereof; the top and bottom surfaces of the wider end portionsof the links being formed as flat or plane surfaces for engagement bythe inner faces of the side bars. Except for a slight tapering of theside walls of the bar of material from the longitudinal center thereofto the top and bottom faces for providing the necessary draft for theforging dies, the bar of material which formed the link was ofsubstantially uniform cross-sectional thickness as distinguished from auniform width of the bar as just described to provide the wider endportions thereof.

It has been found in practice that the weakest point of the keystonechain and the point at which most failures have occurred is at thecomparatively sharp line that marks the demarcation between the thinnercentral section of the link and the tapered section thereof whichconnects the wider end portion of the link with the said central thinnersection.

One of the principal objects of the present invention therefore is toprovide'a new and improved construction whereby there will be no sharpline of demarcation to form a cleavage line as with the Weston chain asheretofore universally constructed.

V 7. As noted above, large quantities of the Weston or keystone chainhave been used for many years in overhead trolley installations in whichthe 1;

chain is supported for movement along a supporting load-carrying I-beamtrack by means of trolley brackets such as disclosed in the patent toJervis B. Webb, No. 1,729,759. As shown in the said Webb patent, a pairof similar bracket members are provided each having an outwardly flaringupper portion having a trolley wheel rotatably mounted thereon forengaging the lower flange of the I-beam and a lower central portionthrough which and the fiat web of a load-supporting clevis or hookmember, bolts are passed to secure the two bracket members and theloadsupporting member in assembled condition, the fiat web of the clevisor load-supporting member passing through the elongated slot of thecenter link so that when the two bracket members and load-supportingmember are secured together, the brackets are held in assembled relationto the I-beam supporting track and to the chain; the bracket thusserving to hold the chain suspended from the supporting track and sothat the weight of the loads which are being supported is carriedentirely by the bracket members and track without any of the load beingtransmitted to the chain which serves entirely as a traction device topropel the trolley brackets and loads along the track.

A further object of the present invention is to so construct the centerlink of a keystone chain as to provide locating surfaces thereon whichwill cooperate with similarly formed'surfaces on a bracket of the typeshown in the said Webb patent in such a manner that the bracket membersand center link of the chain will be rendered automaticallyself-centering when the parts are assembled.

The above and other objects of the invention 'will appear more fullyfrom the following more detailed description and by reference to theaccompanying drawings forming a part hereof and wherein:

Fig. 1 is a side elevation of a center link for a Weston or keystonechain and constructed in accordance with the principles of the presentinvention; 7 I

Fig. 2 is a plan view of the structure shown in Fig. 1;

Fig. 3 is an enlarged sectional detail taken on the line 3-3 of Fig. 2;I V

Fig. 4 is a similar enlarged cross-sectional detail taken on the line 44of Fig. 1;

Fig. 5 is a side elevation of a center link and trolley bracket inassembled condition, and I Fig. 6 is a side elevation showing the mannerin which a center link and pair of side bars are connected by a headedpin.

As shown in the drawings, the link l0, as heretofore explained, isconstructed as a forging and is of the general form of a flat bar-likestructure in the form of an elongated link having side walls H andcurved end sections 12 which enclose an open elongated slot I3.

The link I0 is of symmetrical construction in that both halves of thelink considered either from the transverse central plane or thelongitudinal central'plane are identical in configuration.

As shown most clearly in Fig. l of the drawings, the top and bottomfaces of the link adjacent to the curved end section l2 are providedwith a convex curvature as indicated by the reference character Id. Thepurpose of this curvature is to provide a rounded surface upon which theinner faces of the adjacent side links of the chain bear so that whenthe chain is pass ing around a vertical curve or bend in the conveyorsline of travel, relative movement between the side bars and ends of thecenter links may occur without undue binding or cramping such as wouldoccur if thetop and bottom faces of the thickened end portions of thecenter link were flat and in'relatively close contacting engagement withthe flat inner faces of the side bars as shown in the said Westonpatent.

It will also be noted by referring to Fig. 1 of the drawings that thetop and bottom faces of the center link are also curved or belliedoutwardly at the center thereof, as indicated by the reference characterl5, and that this outwardly convex portion is connected to the convexlycurved portion 14 by curved portion l6 of fairly large radius and sothat the adjacent outwardly curved sections l4 and [5 are merged withthe curved sections 16 in such a way that no sharp dividing line or lineof demarcation is formed such as would provide a line of cleavage.

When the chain is to be used as a part of an overhead trolleyinstallation, the load carrying member 28 is inserted through theelongated slot l3 of a center link l0 and a pair of bracket members 29are bolted together and to the member 2 3 by means of a bolt 30 whichserves to hold the pair of bracket members 29 and the member 28 inassembled condition, the bolt 30 not only serving to hold the trolleywheels 3| of the bracket in engagement with the supporting I- beam trackmember 32, but also to hold the brackets 29 and member 28 securelyunited with the center link E0 of the chain. The lower faces of thetrolley bracket members 29 form shoulders which abut against the topfaces of the side walls H of the center link ill while the lower facesof the said side walls abut with a shoulder 33 formed on each side ofthe load-supporting member 28; the engagement of the shoulders on thebrackets and member 28 serving to secure the chain to the brackets andmaintain said chain in properly spaced relationship to the supportingtrack 32. As will be noted from an inspection of Fig. 5, the lower facesor shoulders of the trolley brackets 29 and the upper faces of theshoulders 33 hold the chain properly spaced below the track 32 with thechain link [0 in proper driving relationship with the brackets 29.

curved to cooperate with the outwardly bellied central portion [5 of thelink; the similarly curved portions of the trolley bracket members andof the central portion of the link serving to automatically locate thebracket properl centrally of the link and to restrict relativelongitudinal movement of the parts after the brackets and link membershave been secured together in assembled condition. It will be noted thatsuch action will prevent the bracket members from sliding longitudinallyinto engagement with the ends of the side bars 26, which engagementwould otherwise interfere with the proper articulation of the chain intraveling over curved portions of the track especially in the case ofvertical curves where one of the side bars 26 must assume a positionmore advanced than the other side bar relative to the adjacent centerlink [0.

While I have shown a satisfactory constructional example of the presentinvention, it will be understood that many changes, variations andmodifications of the specific constructional details may be resorted towithout departing from the spirit or" the appended claims.

I claim:

1. The combination in a trolley conveyor of the type wherein a rivetlesspropulsion chain consisting of a plurality of alternately arrangedcenter links and pairs of side bars are connected by readily detachableheaded connecting pins and said chain is supported at spaced intervalsfrom a supporting track by pairs of load-supporting wheeled trolleybrackets and a cooperating load-supporting member which passes through acenter link of said chain, said brackets and said load-supporting memberbeing held in assembled relationship with said supporting track and saidchain by common fastening means, characterized by the center links ofsaid chain being provided with a thickened central portion formed bysymmetrical outwardly and uniformly curved surfaces on the top andbottom of the side walls thereof, and said brackets and load-supportingmember having symmetrical uniformly and inwardly curved shoulders forengaging the outwardly curved surfaces of said. side link, therebyserving to locate said brackets and loadsupporting members substantiallycentrally of the said link when said parts are secured together inassembled condition.

2. In combination a trolley conveyor bracket and a propulsion chain,said chain comprising alternately arranged center links and pairs ofside bars connected at their respective ends by readily detachableheaded connecting pins, said side bars being provided with recessesforming seats for the heads of said pins, said center links beingprovided with relatively thick ends for holding said side bars in alaterally spaced position such as to cause said heads to become seatedin said recesses when said chain is in its normal assembled and extendedposition and with relatively thin sections adjacent said ends forpermitting said side bars to be moved more closely together duringassembly and disassembly, the central portion of said center link beingformed with symmetrical outwardly and uniformly curved surfaces on thetop and bottom of the side walls thereof, said bracket being providedwith cooperating inwardly curved shoulders for engaging the outwardlycurved surfaces of said center link, thereby serving to locate saidbrackets substantially centrally of said center link in a manner wherebysaid brackets will be held away from contact with adjacent links whichare required to articulate relative to the links supportingly engaged bysaid brackets.

ALEXIS W. LEMMON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,702,803 Webb Feb. 19, 19291,721,759 Webb July 23, 1929 1,906,097 Pribil Apr. 25, 1933 2,411,906Suman Dec. 3, 1946

